To each his own, but it seems unwise to me to hunt in brown bear country with a 243. I'm sure 22 rimfires can kill black bear too but if you bump into a sow with cubs, I suspect you'll want more horsepower.
As for dropping them in their tracks, I've killed black bear with a 45-70, a 376 Steyr and a 338 RUM. They are all good killers, but only the RUM dropped them in their tracks never to get up again. It was like instant death. They weren't little bears. A couple of the bears were pushing 7 ft.
